There has been hitherto proposed an apparatus for reproducing a multi-channel audio signal by use of an array speaker where a plurality of speaker units are disposed in a matrix. That is, one and the same audio signal is input into the respective speaker units simultaneously or with timing varied little by little, so that this audio signal can be output like beams based on the principle of superposition. As shown in FIG. 3, when an audio signal is input to each speaker unit with timing shifted little by little, beams are formed obliquely. When the lag time (delay time) of this timing is set properly, audio beams can be formed in desired directions.
When the delay times of audio signals of respective channels of a multi-channel audio signal are set properly by use of this characteristic of the array speaker and input to the array speaker, the audio signals of the respective channels are output as beams having different directions respectively, for example, as shown in FIG. 1(A).
In the example of FIG. 1(A), an audio signal of a center channel C (referred to as center channel C; the same thing will be applied to the following cases) is output directly toward a listener in the front, while a front left channel FL and a front right channel FR are reflected once by side walls respectively and then arrive at the listener, and a surround left channel SL and a surround right channel SR are reflected twice by the side walls and a rear wall respectively and then arrive at the listener. The listener can listen to the audio signals of the respective channels as if they came from different directions respectively. Thus, multi-channel audio reproduction can be attained artificially.
Patent Document 1: JP-T-2003-510924